How to measure your ring size at home

There are two reliable ways to find a ring size without visiting a jeweller, and they work by measuring different things — pick whichever you actually have available.

Method 1: measure a ring that already fits

This is the more accurate of the two, because it isn’t affected by knuckle size, swelling, or the finger itself at all.

1. Take a ring that fits the intended finger comfortably — not too loose, not tight.
2. Lay a piece of string, dental floss, or a thin strip of paper across the inside of the ring, following its curve.
3. Mark or pinch the point where the string completes the loop.
4. Lay the string flat against a ruler and measure the length in millimetres.

That length is the inside circumference — enter it directly into the ring size converter using the “Circumference (mm)” option.

Method 2: measure the finger directly

Use this only if you don’t have a well-fitting ring to measure.

1. Wrap a strip of paper or string snugly around the base of the finger — where a ring would actually sit, not over the knuckle.
2. Mark where the strip overlaps itself.
3. Measure that length in millimetres.

This method is less precise for two reasons: the base of a finger isn’t perfectly round, so a paper strip flattens slightly against it, and fingers genuinely change size through the day.

What throws the measurement off

• Time of day. Fingers swell slightly in warm weather and after exercise, and are at their smallest first thing in the morning when cold. Measure in the evening, at room temperature, for the most representative result.
• Which hand. Most people’s dominant hand runs very slightly larger. Measure the finger the ring will actually be worn on.
• Knuckle vs. base. If the knuckle is noticeably larger than the base of the finger, size for comfortable passage over the knuckle, not just a snug fit at the base — otherwise the ring won’t go on at all.
• Wide bands sit tighter. A wide, flat band at a given size will feel snugger than a thin, rounded one at the same nominal size, because more of the band’s surface touches the finger. If ordering a wide band, many jewellers recommend going up half a size from a measurement taken with a thin reference ring.

Once you have a measurement in millimetres, the ring size converter gives you the matching US/Canada, UK/Australia, EU and Japan sizes in one step.